Core C is a facility designed to provide state-of-the-art mouse and rat husbandry, veterinary care, mouse colony management and a genotyping service. Its aims are: 1) to maintain breeding colonies of knockout mouse lines, including estrogen receptor subtype a .(ERKO) and P (pERKO) knockouts, P450 estrogen aromatase knockouts (ARKO), and cocaine and amphetamine regulated transcript (CART) knockouts of both sexes;2) to screen via standard genotyping for selection of breeders, for colony expansion, and for supply of animals to projects within the program;and 3) to provide additional husbandry and special care needs for rodent models purchased from vendors or provided by collaborators, including tfm rats and reproductively senescent male (RSM) and female (RSF) rodents (Wistar rats, C57BL/6 mice). This core facility will be a shared resource of the program and will play a central role in our investigations of sex steroids and neuroprotection.